Interesting ImagesLenograstim-Induced Nodal Extramedullary Hematopoiesis A Challenging Diagnosis in Lymphoma Evaluation With 18F-FDG PET/CTLeroy-Freschini, Benjamin MD; Nicolae, Alina MD; Iltis-Roux, Aurore MDAuthor Information From the Department of Nuclear Medicine and Molecular Imaging, ICANS; Department of Pathology, Strasbourg University Hospital, Strasbourg; and Department of Medical Oncology, Clinique St Luc, Schirmeck, France. Received for publication January 30, 2020; revision accepted April 8, 2020. Conflicts of interest and sources of funding: none declared. Correspondence to: Benjamin Leroy-Freschini, MD, Department of Nuclear Medicine and Molecular Imaging, ICANS, 17, Rue Albert Calmette, BP 23025, 67033 Strasbourg Cedex, France. E-mail: email@example.com. Clinical Nuclear Medicine: August 2020 - Volume 45 - Issue 8 - p e373-e375 doi: 10.1097/RLU.0000000000003111 Buy Metrics Abstract We report the case of a 23-year-old man with nodal EMH (extramedullary hematopoiesis) occurring during treatment for a stage IIA “gray-zone” lymphoma. Although it is often related to myeloproliferative bone marrow disease, benign etiologies such as lenograstim treatment after chemotherapy can also induce EMH and be responsible for false-positive 18F-FDG PET/CT examinations. In this respect, GLUT overexpression in hematopoietic lineages and macrophages of the inflammatory environment are responsible for increased 18F-FDG uptake. Histopathologic confirmation of new hypermetabolic lesions on follow-up PET/CT may be required when the new lesions do not conform with the treatment responses in the preexisting lesions. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.